1. Field of the Invention
The invention pertains generally to the field of guided wave optical communication systems and more particularly relates to low loss optical-data single fiber terminal devices for performing multi-mode access coupling in data distribution networks, as well as multiplexing and demultiplexing functions in electrooptical data processing apparatus.
2. Description of the Prior Art
Experience in guided optical data communication methods, while earlier intensely concerned with the fiber optic bundle and single mode integrated optical techniques, now leads to the conviction that an intermediate approach, the multi-mode, single optical fiber technology, can be most successfully applied to a wide variety of communication problems, especially where moderate bandwidth and moderate distances are involved. Fabrication of passive interconnectors is simplified and the packing fraction losses characteristic of the fiber bundle method are eliminated. The single mode technology has been significantly advanced; however, important unsolved coupling problems still remain.
Simple light sources exist easily capable of coupling considerable power into available multiple mode, single fiber guides, and quite adequate photodetector devices for detecting the flow of light through such single fiber guides are also available. Evidently, the scheme for multiple mode, single fiber communication would be made useful if concepts existed for electrically controlling the routing of optical signals, so that data bussing, multiplexing, demultiplexing, and switching functions could be performed totally in the optical domain by reliable and inexpensive data terminals.